1. Field of the Invention
The present invention relates to devices and methods for quantifying a radiation dosage, and, more particularly, to devices and methods for quantifying a dosage of ultraviolet and x-radiation and high-energy particle radiation.
2. Description of Related Art
As it is known that certain wavelengths of radiation can be harmful to living creatures, it is desirable to be able to measure a "local dose" of incident radiation in order to monitor incident radiation. Physical photometers measure an irradiance, or instantaneous rate; a biologically effective dose must be obtained from these data by integrating with a DNA absorption spectrum. This total dose is important for correlating with a biological response such as cell mortality, mutation, or carcinogenesis.
The biologically effective UV radiation that reaches the Earth's surface is generally in the range of 290-320 nm, and it is known that, presumably owing to the destruction of the Earth's ozone layer, the incident amount in this range has been increasing with time.
It is known to use deoxyribonucleic acid (DNA) as a molecular dosimeter for ultraviolet radiation, since total dose data are provided, and since the peak of DNA absorption is approximately 260 nm. It is also advantageous to use DNA, because the principal target for UV damage in living organisms is DNA.
Naked DNA is known to provide "worst-case" damage data, since DNA in vivo is usually afforded some protection by surrounding structures such as nucleoproteins and can be repaired by intracellular mechanisms. Therefore, a DNA dosimeter records the maximum UV damage sustainable by such a molecule at the place and time it is exposed.
It has been known to use radioactive .sup.3 H-labeled DNA as a solar dosimeter in the ocean; however, a problem associated with this technique is the potential for introducing an undesirable material into the environment.
van Houten et al. (Amplifications 10, 10-17, 1993) have quantified the average lesion frequency in UV-irradiated E. Coli lacZ and lacI genes with the polymerase chain reaction.
It is also known that x-radiation and high-energy particle radiation cause damage to DNA.
At present there exists no convenient, portable, inexpensive, safe, compact device and method for measuring a biologically effective dosage of radiation, specifically, a dosage of UV and x-radiation and high-energy particle radiation, incident upon a selected object or area over a desired time period.